The Raspberry Pi is a stripped-down Linux PC consisting of a tiny circuit board, an ARM-based CPU, and a graphics processor -- and inspiration for creative hacks

Since the $35 credit card-size Raspberry Pi went on sale last February, hackers have made it into a game console to a Linux laptop to a supercomputer. And an estimated 1 million PC hobbyists have snatched one up. The U.K.-based Raspberry Pi Foundation says it's become a phenomenon. "There's no sign of a slowdown in demand," says Mike Buffham, of Premier Farnell, one of two distributors.

The Pi's aim was to inspire kids to write code and build computers, but they're also a hit with adults. Its core is a stripped-down Linux PC with a tiny circuit board, an ARM-based CPU, a graphics processor, and several pins and ports. And from that blank circuit board of a canvas, the creativity flows.

Straight out of the box, you can plug the Raspberry Pi into your TV and add a keyboard. It will never replace your Windows PC, as we found out in our test of the Raspberry Pi , but you can use it for simple things such as word processing, casual games, and video streaming.

You can also glean Raspberry Pi know-how from an online community. The Raspberry Pi Foundation's app store is a hub for sharing computer designs, applications, and tips. Most of the apps are free, though some games and utilities require a small fee. You can buy the Raspberry Pi from one of the foundation's two distributors: Premier Farnell/Element 14 and RS Components.

Just because the Raspberry Pi is small doesn't mean it's a toy, says Simon Cox, a computer engineer at the U.K.'s University of Southampton. Cox and a team of engineers built a supercomputer by tying 64 Raspberry Pi systems together. Cox also enlisted the help of his 6-year-old, Lego-obsessed son, who built the supercomputer's rack out of the plastic building blocks.

The University's computer cluster has a total of 64 processors and one terabyte of memory (care of 64 different 16GB SD cards, one for each Raspberry Pi), and uses ethernet switches to link the systems.

Scott Garner's Raspberry Pi creation mixes vegetables, music, and wordplay. His BeetBox allows users to play drumbeats by touching real beets. Garner says that his BeetBox was easy to put together, thanks to the versatility of the Pi platform. "The biggest challenge was getting [the Pi] to communicate with the capacitive touch sensor," he says. The beets, however, proved less pliable than the Raspberry Pi. "Things got tricky when the vegetables dried out. Their capacitance changed, which threw the sensor off," Garner says.

"I just wanted to see if it was possible to make an ultraportable, mobile Raspberry Pi that you can take to go," explained Nathan Morgan, founder of the laptop parts site Parts-People.com.

Morgan's Pi-to-Go minicomputer sports a 640-by-480 pixel display, a touchpad, a 64GB solid-state drive, and support for Wi-Fi, Bluetooth, and HDMI. "It's not the lightest or thinnest handheld," Morgan said in an interview, "But I didn't care about that when I was building it. I just wanted it to meet all the criteria for being a portable Pi."

While this Beer Keyboard isn't the most practical peripheral in the world, it's possibly the most inebriating. Powered by Raspberry Pi, this QWERTY keyboard for the over-21 crowd is tricked out with 44 beer cans from a Prague-based brewery. The company Robofun Create built the system, which requires you to tap the letters on the tops of beer cans to produce letters on a plasma screen above it (not shown).

A group called FishPi is ready to put the spunky Raspberry Pi to sea. It's planning an Atlantic crossing for a drone boat with its navigational systems controlled by the single-board computer.

Measuring 20 inches from stem to stern, the vessel is powered by a 130-watt solar panel. As the boat crosses the Atlantic, it will collect scientific measurements. "We wanted to do something that went outside of the normal bounds of conventional thinking," the group explained on its website.

When Jeroen Domburg bought a Raspberry Pi, he didn't know what he was going to do with it. "It's always useful to expand your toolset with something powerful and cheap," he has said. What he eventually cooked up is perhaps the smallest arcade-style gaming cabinet in the world. The cabinet is made of laser-cut plastic and has a 2.4-inch TFT display.

SK Pang Electronics took a slightly different tack in creating a portable computer with the Raspberry Pi board. It uses the monitor from the rear-view camera system of an automobile -- a choice that required some power-supply tinkering -- as well as a mini-wireless keyboard, a USB power pack, and a cool laser-cut transparent base.

Raspberry Pi owners hungry for a serious challenge can consider building a solar-powered FTP server. The setup here includes a custom-built Raspberry Pi case with a solar panel on one side, and on the other side are compartments for the computer with holes in all the right places for I/O ports and four AA rechargeable batteries. "You'll always have instant access to all your digital files, from anywhere with an Internet connection, and it won't cost a penny on your electricity bill," says David Hayward, who provides full details about the project here.

Linux software engineer and photographer David Hunt had been thinking about embedding a computer in a DSLR camera for years, but it cost too much. Then came the Raspberry Pi to smash that hurdle. The $35 PCB allowed him to repurpose one of his old battery grips into a camera accessory that can transmit just-shot images in real time to a computer via Wi-Fi, and also enables control of the camera remotely from a computer. "There’s plenty of work to be done on the software side of things, but the prototype is working," he says.

If he gets too frustrated, he can just pick up an Eye-Fi wireless card for his camera. But that might be a bit too easy.

Retro computer fans will love celebrity console-modder Ben Heck's Raspberry Pi project. It uses a retro keyboard for the Raspberry Pi case, giving it the flavor of an old Commodore 64 computer. The case is made of laser-cut wood with a hinged keyboard that can be lifted to get at the single-board computer beneath it.

Chasing high-altitude balloons has become sport for many who send GPS-enabled gear to the outer limits of the Earth's atmosphere and then chase after it as it floats down. To one-up his ballooning friends, Dave Akerman outfitted his payload with a custom Raspberry Pi computer that sported a GPS radio, a webcam, and various sensors. He claims that, thanks to his Sky Pi rig, he was able to capture some of the highest images ever sent down from an amateur flight. Of course, he blogged about his achievement and also posted a fascinating Flickr collection documenting his balloon's voyages.